JP5781288B2 - Cavity structure with adhesive interface made of getter material - Google Patents

Description

  The present invention relates to a structure comprising a hermetically sealed cavity in which, for example, a getter material is placed to control the atmosphere filled in the cavity, the getter material also comprising adhesion between the elements forming the cavity. Works to complete the interface. The structure according to the invention may in particular be an encapsulated structure of microelectronic and / or nanoelectronic devices. The invention also relates to a manufacturing method for such a structure.

  MEMS type (electromechanical microsystem), NEMS (electromechanical nanosystem), MOEMS (optoelectromechanical microsystem), NOEMS (optoelectromechanical nanosystem), or even an infrared detector for proper operation Some microelectronic and / or nanoelectronic devices, such as, need to be enclosed in a cavity in which the atmosphere (gas properties, pressure) is controlled. These devices are typically made together on the same substrate (wafer), e.g. silicon, and then generally transfer the silicon cover onto the substrate, and then seal the cover with the substrate It is individually enclosed in a sealed cavity formed by sealing. Previously known hermetic sealing techniques include anodic sealing between the glass substrate and the silicon cover, metal eutectic sealing, direct sealing between two silicon elements, and two metal elements It is thermocompression bonding between.

  By adding the getter as a thin layer within the cavity, the pressure spreading within the cavity is specifically controlled. As described in U.S. Pat. Nos. 5,099,086 and 5,037,086, it is known to deposit getter material as a thin layer on the inside of a cavity, on the side of a device, or in contact with the cover of a cavity. In essence and / or because of its microscopic or nanoscale form, a getter material is a material that is absorptive and / or adsorptive with respect to gaseous molecules and thus when placed in a closed environment A gas pump can be formed. Thus, such getter materials control the pressure within the cavity in which the microelectronic and / or nanoelectronic devices are encapsulated. Non-evaporable getter materials are, for example, metals such as titanium, zirconium, hafnium, or metal alloys of these metals or compatible metals.

  FIG. 1 shows a first example of an encapsulation structure 10 comprising a substrate 12 that encloses a device 14. Device 14 is encapsulated in a cavity 16 formed between substrate 12 and cover 18 that are sealed to each other by sealing beads 20. A getter material 22 deposited to contact the cover 18 is also disposed within the cavity 16.

The encapsulation structure 10 has two major drawbacks:
-It is difficult to control the airtightness of the sealing beads 20 after melting.
-Difficulties in controlling the dimensions of the sealing bead 20 can cause the bead to spread during the melting process, possibly resulting in functional failure of the encapsulated device (movable mass is affected, short circuited, etc.).

  FIG. 2 shows a second example of an encapsulation structure 30 comprising an encapsulation device 14 in a cavity 16 formed between the substrate 12 and the cover 18. Compared to the encapsulation structure 10 shown in FIG. 1 where the cover 18 is attached to the substrate 12 using sealing beads 20, the substrate 18 of the cover 18 and the silicon-based encapsulation structure 30 are It is sealed directly. In addition to the getter material 22 deposited in contact with the cover, the encapsulation structure also includes a portion 24 of getter material disposed within the cavity 16 to contact the substrate 12.

  Encapsulation structure 30, including a direct assembly between two silicon-based elements, still requires processing aimed at improving molecular adhesion at ambient temperature before the interface is cured by heat treatment. These treatments, dried and / or humidified, are only slightly compatible with the presence of the getter, thus significantly reducing the pumping capacity and thus limiting the minimum pressure achievable by this type of structure. There is a risk.

US Pat. No. 6,897,551B2 International Publication No. 2009 / 088284A1

  The object of the present invention is to propose a novel structure designed, for example, to encapsulate the device, in order to ensure a considerable hermeticity in the cavity formed in the structure.

  For this, it comprises at least one first substrate and at least one cavity defined by at least one second substrate attached to the first substrate using at least one adhesive interface, A structure is proposed in which at least one portion of at least one getter material partially disposed within the cavity also forms at least a portion of the adhesive interface.

  At least one getter comprising at least one cavity defined by at least one first substrate and at least one second substrate attached to the first substrate using at least one adhesive interface The first part of the at least one first part of the material forms part of the adhesive interface, the second part of the first part of the getter material is disposed in the cavity, and the first part of the getter material The first portion is arranged to be placed against the first substrate or the second substrate, and the adhesive interface is at least thermocompression bonded to the first portion of the first portion of the getter material Further comprising at least a portion of a second portion of one getter material, wherein the second portion of getter material is disposed when the first portion of getter material is disposed in contact with the first substrate. Placed in contact with the two substrates or the first part of the getter material When it is placed in contact with the second substrate being placed in contact with the first substrate, the structure is also proposed.

  Thus, the same portion of getter material forms part of the adhesive interface and forms a gas absorption and / or adsorption getter within the cavity. Also, when this portion of getter material is placed around the cavity, all wide getter surfaces are more easily reached. For structures containing sealing beads, the final pressure spread within the cavity is controlled by sizing the surface of the getter material exposed inside the cavity.

  Assuming that the two portions of the getter material that form the bond interface are thermocompression bonded together, as a result, the bond interface is formed by the mutual diffusion of the getter materials.

  A cavity comprising at least one hermetically sealed cavity defined by at least one first substrate and at least one cover attached to the substrate using at least one adhesive interface; A structure is also proposed in which at least one part of at least one getter material partially disposed therein also forms at least part of the adhesive interface.

  The second substrate can form a cover.

  The cavity can be hermetically sealed.

  The first and / or second portion of getter material may be a thin layer, i.e., having a thickness of less than about 2 μm.

  The adhesion interface further comprises a portion of a first substrate made of oxide and / or nitride and / or glass and / or a second substrate made of oxide and / or nitride and / or glass. Can do.

Thus, the adhesive interface includes a portion of the getter material, which is
-Contact with other parts of the same type or different getter material,
-Contact with a surface (of the first substrate and / or the second substrate), for example oxidized and / or nitrided and / or glassy.

  The portion of getter material, referred to as the first portion of getter material, can be placed in contact with the first substrate or the second substrate, and the adhesive interface is at least of the first portion of getter material. It can also include at least a portion of a second portion of at least one getter material that is disposed in contact with the portion, wherein the second portion of getter material is a first portion of getter material that is a first portion. Placed in contact with a second substrate when placed in contact with the second substrate, or arranged such that the first portion of getter material is in contact with the second substrate Sometimes it can be placed in contact with the first substrate.

  A seal between the first substrate and the second substrate, e.g. a hermetic seal, can be obtained by a connection made between two parts of a getter material, e.g. a metal material, e.g. thermocompression bonding, Thus, it can have a considerable hermeticity to ensure that the atmosphere provided in the cavity lasts for a long time. These portions of getter material adhering to each other can preferably both be formed as a thin layer, for example, a layer having a thickness ranging from about 100 nm to several hundred nanometers, and the thickness of the getter grains Has an increasingly smaller roughness because of reduced thickness and / or size.

  The getter material of the first portion and the second portion of the getter material may have different thermal activation temperatures. In this case, the thermal activation temperature of the first part of the getter material may be lower than the thermal activation temperature of the second part of the getter material. Thus, two portions of getter material that are thermally activated at two different temperatures have a higher degree of vacuum in the cavity of the structure than if these portions consist of getter materials with similar thermal activation temperatures. To reach. Then, in fact, a portion of the first portion of the getter that is placed inside the cavity will be exposed to a heat balance that is greater than necessary for its activation, resulting in saturation of the layer. Can therefore result in a higher degree of vacuum compared to the opposite case.

  The structure is in contact with the first substrate and / or in contact with at least one first electrical contact disposed within the first substrate and the second substrate; and And / or further comprising at least one second electrical contact disposed within the second substrate, wherein the first electrical contact and the second electrical contact form at least an adhesive interface, the first portion of the getter material And can be electrically connected together using part of the second part. The portion of the getter material that forms the adhesive interface thus also forms an electrical connection that electrically couples the electrical contacts formed across the structure.

  The structure can further include a device disposed within the cavity. In this way, the structure forms the encapsulation structure of the device.

  The structure can further comprise at least one other portion of at least one getter material disposed within the cavity, eg, disposed in contact with the second substrate. This other portion of the getter material forms an adhesive interface for gas absorption and / or adsorption within the cavity, and a portion of the first portion of getter material disposed within the cavity is completed.

  The portion of the getter material is a first substrate using at least one first portion of at least one material, for example a metallic material, suitable for modifying the thermal activation temperature of the portion of the getter material. The second part of the getter material is disposed in contact with the material or the second substrate and / or the structure includes a second part of the getter material, the heat of the second part of the getter material Arranged to contact the second substrate or the first substrate, respectively, using at least one second part of at least one material, for example a metallic material, suitable for modifying the activation temperature sell. These parts of the material for adjusting the thermal activation temperature of the getter material, consisting of copper or aluminum, specifically lower the thermal activation temperature of one or more parts of the getter material and thus the heat seen in the rest of the structure Limit the balance. Also, these adjustable metal portions of the heat activation temperature of the getter material may be between the first substrate or the second substrate and the first and / or second portion of the getter material. Eliminate any chemical interactions that may intervene in If electrical contacts are formed in the structure and are electrically connected together by these portions of the getter material, this preferably forms a conductive adjustment portion between the portions of the getter material and the electrical contacts. .

  The portion of the second portion of getter material may molecularly adhere to the first portion of the first portion of getter material.

The present invention also relates to a method of forming a structure, at least
-Forming at least one portion of at least one getter material in contact with the first substrate and / or the second substrate;
The second substrate is attached to the first substrate and defined by the first substrate and the second substrate using at least one adhesive interface formed at least in part by a portion of the getter material; Forming at least one hermetically sealed cavity formed, wherein said portion of getter material is also partially disposed within the cavity.

The proposed structure formation method is at least:
-Forming at least one portion of at least one getter material in contact with the substrate or cover;
Attaching the cover to the substrate, forming at least one hermetic cavity defined by the substrate and the cover using at least one adhesive interface formed at least in part by a portion of the getter material; The portion of the getter material includes a step in which a portion is also disposed within the cavity.

The proposed structure formation method is at least:
Forming at least one first portion of at least one getter material in contact with the first substrate or the second substrate;
-At least one second portion of the at least one getter material so as to contact the second substrate when the first portion of getter material is arranged to contact the first substrate, or Forming the first portion of getter material to contact the first substrate when positioned to contact the second substrate;
Attaching the second substrate to the first substrate by thermocompression bonding a first portion of the first portion of the getter material to at least a portion of the second portion of the getter material; Forming at least one cavity defined by the substrate and the second substrate, wherein the second portion of the first portion of the getter material is disposed within the cavity.

To perform such a thermocompression bonding process to perform the connection of two substrates,
-No gas release in the cavity due to getter material when connected,
-Contrary to connections involving melting of the getter material, thermocompression prevents the getter material from crashing and thus has various advantages of good dimensional control of the adhesive interface.

  The method includes placing at least one device in a cavity so that the second substrate is disposed in the cavity after the second substrate is attached to the first substrate prior to the step of forming the first portion of getter material. A step of forming in and / or in contact with the first substrate.

  The step of forming the first portion of getter material may include at least one step of depositing the first portion of getter material as a thin layer on the first substrate and / or the second substrate. it can.

  The method includes the step of attaching at least one second portion of the at least one getter material to the other portion of the getter material, referred to as the first portion of the getter material, prior to attaching the second substrate to the first substrate. When the first portion of the getter material is placed in contact with the first substrate, or the first portion of the getter material is placed in contact with the second substrate. In some cases, the method may further include a step for forming the first substrate so as to be in contact with the first substrate.

  The step of attaching the second substrate to the first substrate includes thermocompression bonding at least a portion of the first portion of the getter material to at least a portion of the second portion of the getter material. A step of performing at least one step can be included.

  The step of attaching the second substrate to the first substrate includes the step of attaching a first portion of the first portion of getter material to the portion of the second portion of getter material. ) To complete the bonding.

  In this case, the method may further include a consolidation step via a heat treatment of the molecular adhesion that improves adhesion by molecular adhesion without disturbing the getter material after completion of molecular adhesion.

  The step of depositing the first and second portions of the getter material is preferably performed by PVD (Physical Vapor Deposition), e.g., by cathodic collapse or vapor deposition to a minimum thickness (e.g. about 100 nm). Equal or less than about 2 μm) and this portion of getter material will have minimal roughness.

  The step of forming the first portion or the second portion of the getter material in contact with the second substrate is disposed in the cavity after the second substrate is attached to the first substrate. As such, at least one other portion of the getter material can be formed in contact with the second substrate.

  The method includes: a first portion of a getter material prior to attaching the second substrate to the first substrate and after forming the first and second portions of getter material. And / or a second layer of oxide and / or nitride can be formed, which can be eliminated during the connection process, diatomic oxygen and / or diatomic nitrogen An oxidation and / or nitridation step of the first portion and / or the second portion of the getter material that can be performed in a dry atmosphere of Thus, these protective layers expose portions of the getter material to ambient air without being oxidized or contaminated by air or water vapor present in the air. When performing assembly at a temperature above the activation temperature of the getter material where the activation temperature is highest, for example, in the range of about 300 ° C. to 450 ° C., the portion of the getter material has its protective layer Absorbs and accordingly eliminates the contact resistance associated with the presence of this protective layer of oxide and / or nitride (especially advantageous when parts of the getter material electrically connect the electrical contacts together) ). Thus, the thermocompression performed between portions of the getter material is complete when the protective layer is eliminated by the action of the pressure applied between the portions of the getter material or the temperature to which the portions of the getter material are exposed. can do.

The oxidation and / or nitridation steps are performed, for example, immediately after depositing the getter and in the same machine, thereby avoiding exposure of the getter material to ambient air. For example, in the case of a getter deposited by a deposition method using PVD, at a gas partial pressure (oxygen or nitrogen) compatible with the deposition apparatus, that is, at a pressure of about 10 ^-2 mbar or more, or about 1000 mbar. The treatment can be carried out at pressures ranging from 10 to ² mbar and / or at temperatures from about 50 ° C. to 120 ° C. and / or for a period of approximately 1 min to 10 min. The highest priority parameter in performing this protection is temperature, and the pressure may be variable over a wide range from about 1000 mbar to 10 ^-2 mbar.

  This method involves a secondary vacuum between the oxidation and / or nitridation step and the connection step at a temperature approximately 50 to 150 ° C. lower than the activation temperature of the portion of the getter material having the lowest activation temperature. The method may further include performing a heat treatment step of the first portion and / or the second portion of the getter material, for example, a desorption step.

  The first and second portions of getter material can be arranged to contact at least one first electrical contact and one second electrical contact, respectively, the first electrical contact and the second electrical contact One of the electrical contacts can be disposed in contact with and / or within the first substrate, wherein the first electrical contact and the second electrical contact are The other can be placed in contact with the second substrate and / or within the second substrate, and the connecting step can be performed using the first and second portions of the getter material. One electrical contact and a second electrical contact can be electrically connected together.

  The method includes at least one material suitable for modifying the thermal activation temperature of the first portion of getter material, e.g., at least one of a metal material, prior to the step of forming the first portion of getter material. Forming a first portion in contact with a first substrate or a second substrate, wherein the first portion of getter material can be disposed at least on the first portion of the material, The method can further include and / or if the method includes forming a second portion of the getter material, the method can include the step of forming the second portion of the getter material before At least one material suitable for modifying the heat activation temperature of the second part, for example at least one second part of the metallic material, in contact with the second substrate or the first substrate, respectively The second portion of getter material is at least a second May be located in the metal portion may further comprise a step. Utilizing ductile materials or materials with low Young's modulus to form this part of the activation temperature or these parts of the control material, possibly reducing the roughness of the getter material and receiving heat It may be advantageous to take advantage of the flexibility that may be able to accommodate the residual mechanical constraints created by assembly.

  The method further includes one or more thermal activation steps of one or more getter materials disposed in the cavity after attaching the second substrate to the first substrate. Can do.

  The invention will be better understood by reading the description of a non-limiting embodiment which is purely shown with reference to the accompanying drawings.

FIG. 3 clearly illustrates the encapsulation structure of a prior art device. FIG. 3 clearly illustrates the encapsulation structure of a prior art device. FIG. 3 illustrates a structure that is the subject of the present invention, eg, designed to form an encapsulation structure of a device, according to a first embodiment. FIG. 4 illustrates a structure that is the subject of the present invention, eg, designed to form an encapsulation structure of a device, according to a second embodiment. FIG. 4 illustrates the steps of a method of forming a structure that is also the subject of the present invention, according to a particular embodiment. FIG. 4 illustrates the steps of a method of forming a structure that is also the subject of the present invention, according to a particular embodiment. FIG. 6 illustrates a structure that is the subject of the present invention according to a third embodiment.

  The same reference numbers are used for the same, similar or equivalent parts of the different figures described below to make it easy to refer to all the figures.

  The various parts shown in the figures are not necessarily to scale, in order to make the figures easier to read.

  The various possibilities (modifications and embodiments) have to be understood as not mutually exclusive and can be combined.

  First, referring to FIG. 3, this shows a structure 100 which serves here as an encapsulation structure of the device 104 according to the first embodiment.

  The structure 100 is a first substrate made of a semiconductor, for example silicon, on which microelectronic and / or nanoelectronic devices 104 of, for example, MEMS, NEMS, MOEMS, NOEMS type or infrared detectors of the microbolometer type, for example, are arranged. A material 102 is provided. The device 104 is encapsulated in a cavity 106 formed between the substrate 102 and the second substrate 108, which is here made of a semiconductor such as silicon, which also forms a cover. The connection between the second substrate 108 and the first substrate 102 is part of the first portion of the getter material 110 deposited on the first substrate 102, all on the device 104. 114, and a second portion of getter material 112 deposited in contact with the second substrate.

  The first portion 110 and the second portion 112 of getter material have a thickness in the range of, for example, about 100 nm to 2 μm, and one or more metallic materials, such as titanium and / or zirconium and / or It consists of vanadium and / or any other metal having absorption and / or gas adsorption properties.

  Thus, the adhesive interface between the first substrate 102 and the second substrate 108 is formed by portions 110, 112 of these getter materials that are thermocompression bonded to each other. The portions 110, 112 of getter material are now made in the form of a thin layer, and therefore these portions have a thickness of about 2 μm or less. Also, these portions 110 and 112 of the getter material are deposited here by PVD (Physical Vapor Deposition), for example cathodic collapse or evaporation, and these portions 110 and 112 will have a slight roughness. , Having affinity with the thermocompression performed between these portions 110 and 112.

  FIG. 3 illustrates that the first portion 114 of the first portion 110 of getter material, together with the second portion 112 of getter material, forms an adhesive interface between the first substrate 102 and the second substrate 108. Forming, and the second portion 116 of the first portion 110 disposed within the cavity 106 does not form an adhesive interface. Thus, the first portion 110 of the getter material forms an adhesive interface between the first substrate 102 and the second substrate 108 and also of the getter material itself, i.e. within the cavity 106. It serves to perform gas absorption and / or adsorption, thereby controlling the atmosphere within this cavity 106. This role of gas absorption and / or adsorption filled by the second portion 116 of the first portion 110 of the getter material contacts the second substrate 118 in the cavity 106 and opposite the device 104. Also filled by a portion 118 of getter material arranged in this manner, the material of this portion 118 is the same as the material of the second portion 112 of getter material, for example.

  The getter materials of portions 110 and 112 may be essentially the same or not the same. Also, the getter materials of portions 110 and 112 can have the same thermal activation temperature. However, these getter materials are preferably selected such that their thermal activation temperatures are different. Also, these getter materials are preferably in the cavity 106, in the reverse case (the getter material of portion 110 has a thermal activation temperature higher than the heat activation temperature of the getter material of portion 112) or of the getter material. The part including the part where the getter with the lowest thermal activation temperature is placed in the cavity, which generates a higher degree of vacuum when the two parts 110 and 112 have the same thermal activation temperature, i.e. It is chosen to be the getter material for the first part 110 of the example. The heat activation temperature of the getter material is equal to about 450 ° C., for example, when portions 110 and 112 are made of titanium.

  In one alternative embodiment, the portions 110 and 112 of the getter material are not arranged to be in direct contact with the first substrate 104 and the second substrate 108, but their metal portions for adjustment of the heat activation temperature of the getter material May be disposed between these portions 110, 112, the first substrate 102 and the second substrate 108. For example, these metal parts consisting of Cu and / or Ni and / or Pt and / or Ag and / or Ru and / or Cr and / or Au and / or Al are used in the case where the getter material parts 110, 112 are in the cavity 106. Change to a temperature that reacts with the atmosphere. In this way, the thermal activation temperature of portions 110 and 112 can be lowered to range from about 275 ° C. to 425 ° C., for example, depending on the metal nature of the conditioning metal portion and the nature of the getter material. It is.

The thickness of these metal parts is, for example, in the range from about 50 nm to 500 nm. These control metal parts have a coefficient of thermal expansion within the range of about 5.10 ^-6 / ° C to 23.10 ^-6 / ° C and their use temperature (the temperature at which these parts are deposited) and their melting temperature. It can have a ratio in the range of 0.1 to 0.3. The conditioning metal part is deposited, for example, by vapor deposition. Other characteristics relating to these adjustment parts are described in US Pat.

  FIG. 4 illustrates a structure 200, here forming the encapsulation structure of the device 104, according to a second embodiment. With respect to the encapsulation structure 100 illustrated in FIG. 3, the encapsulation structure 200 includes an electrical contact 202 formed in the first substrate 102, as well as a second substrate 108 that forms the walls of the cavity 106. An electrical contact 204 is provided that is disposed on one surface 206. Electrical contacts 202 and 204 are electrically connected together using portions 110 and 112 of getter material made of metal. Thus, the portions 110 and 112 not only form a hermetic seal between the second substrate 108 and the first substrate 102, but also to electrically connect the electrical contacts 110 and 112 together Also used. The second portion 116 of the first portion 110 of getter material is also used to absorb and / or adsorb the gas present in the cavity 106, similar to the encapsulation structure 100. Finally, with respect to the encapsulation structure 100, the encapsulation structure 200 does not include the getter material 118.

In one variation, it is possible to treat the getter material in portions 110 and 112 so that they are protected from ambient air and in particular from water vapor before sealing between the portions 110 and 112 of the getter material. is there. For this purpose, diatomic oxygen (O ₂ ) and / or dry diatomic nitrogen (N ₂ ) is a temperature in the range from about 50 ° C. to 120 ° C., for example a temperature equal to about 100 ° C. It is injected in-situ, ie into the deposition chamber of the getter material, with a pressure spreading into the deposition chamber in the range of 10 ⁻³ mbar. Dry oxidation of the getter material of portions 110 and 112 by placing the getter material in the presence of dry diatomic oxygen and / or dry diatomic nitrogen for a period of a few minutes, for example, a period ranging from about 1 min to 10 min And / or nitridation occurs, and a protective layer made of oxide and / or nitride is formed on the surface of the getter material. If the getter material is later exposed to ambient air, the resulting protective layer protects the getter material from chemical changes that can be caused by gases present in the ambient air, in particular, these gases are It is because it is absorbed and / or adsorbed by the protective layer without contaminating it. Accordingly, the first substrate 102 and the second substrate 108 can be stored in ambient air before being hermetically sealed together. Other modifications already described in connection with the first embodiment (metal part for adjusting the thermal activation temperature of the getter material, the getter material has a different or different thermal activation temperature) This can be applied to the second embodiment.

  Next, the steps of the method for making the encapsulation structure 100 are described with respect to FIGS. 5A and 5B.

  As illustrated in FIG. 5A, the second semiconductor-based substrate 108 is first made of, for example, silicon and a hollow portion 101 is formed that forms at least a portion of the cavity 106. A thin layer of getter material is then deposited on the second substrate 108, for example by DVD deposition, and then formed, for example, by photolithography and etching, whereby a second layer of getter material 112 around the hollow portion 101. As well as a portion 118 disposed around the hollow portion 101 and intended to face the device 104. In a modified embodiment, the second portion 112 and the portion 118 may be lift-off deposited (a sacrificial mask formed on the second substrate 108, particularly if the second substrate has a substantial topology. It is also possible to form directly by deposition) or by deposition with a stencil.

  A first portion 110 of getter material is then deposited on the first substrate 102 around which the device 104 is formed, around the device 104 (FIG. 5B). This first portion 110 of getter material can be formed by using techniques similar to those already described for forming the second portion 112 of getter material.

  In one variant, first a metal part for adjusting the thermal activation temperature is first formed on the first substrate and / or the second substrate, for example by deposition, photolithography and etching, and then the getter Part of the material can be formed on these control metal parts. It is also advantageous to deposit metal parts and getter material one after the other and then form by photolithography and etching.

  Then, the assembly between the first substrate 102 and the second substrate 108, for example, controlling the atmosphere inside the enclosure and applying heat to the first substrate 102 and the second substrate 108 While performing in a sealed enclosure that applies pressure, resulting in a connection by diffusion between the portions 110 and 112 of the getter material, and the second substrate 108 is hermetically sealed to the first substrate 102. The This results in the encapsulation structure 100 shown in FIG. 3, where the first portion 114 of the first portion 110 of getter material is thermocompression bonded to the second portion 112 of getter material.

  Forming the encapsulation structure 200 shown in FIG. 4 may include performing a process similar to that described above for forming the encapsulation structure 100.

  It is possible to connect the two substrates 102 and 108 via molecular adhesion between the first portion 114 of the first portion 110 of getter material and the second portion 112 of getter material.

  If a protective layer of oxide and / or nitride is deposited on the portions 110 and 112 of the getter material before assembling the second substrate 108 on the first substrate 102, and also the first substrate If 102 and / or the second substrate 108 is exposed to ambient air, a heat treatment under secondary vacuum is performed at a temperature equal to, for example, about 150 ° C., or more generally, the activation temperature Before the second substrate 108 is hermetically sealed to the first substrate 102 at a temperature about 50 ° C. to 150 ° C. lower than the lowest getter activation temperature for a period of about 10 min to 30 min. Run to desorb the gas that is adsorbed and / or absorbed by the protective layer. Next, when sealing, the protective layer disappears under the effect of pressure and temperature applied between the portions 110 and 112, and then diffusion between the portions 110 and 112 causes metal / metal bonding. Forming a hermetic seal of the cavity 106.

  Next, a structure 300 obtained by three-dimensional assembly of three substrates with microelectronic and / or nanoelectronic components (e.g., CMOS type, sensor, etc.) referenced in 40, 50, and 60 is shown in FIG. Will be described. Each of the three substrates 40, 50, and 60 is referred to as 80, 82, and 84, respectively, and a layer 110a of getter material that is also used to connect the substrates 40, 50, and 60 together, 110b and via holes or electrical contacts electrically connected together by 112a, 112b. The first substrate 40 here forms the base of the structure 300 and also serves as the gripping part of the structure 300. The first substrate 40 is, for example, a substrate comprising a CMOS type device, which includes, for example, one or more sensors connected to the former via, for example, the substrates 50 and / or 60. Used to control. Substrates 50 and 60 can be reduced in thickness, for example, to more easily restore through electrical contacts. Cavities 302 and 304 are formed between the substrates 40 and 50 and between the substrates 50 and 60, respectively. Further, the layer portions 111 a and 111 b of the getter materials 110 a and 110 b are disposed inside the cavity 302.

  Getter materials 110a, 110b, 112a, and 112b may or may not be of the same nature. For example, the layers of getter material 110a, 110b can have different activation temperatures than the layers of getter material 112a, 112b. In addition to adjusting the seal formed according to the maximum allowable temperature by the laminated base material, it is described in Patent Document 2 to control the electrical resistance of the internal connection caused by the seal. One or more regulatory sub-layers can be added to the structure 300. For example, if the substrate 60 is sensitive to temperature, a getter that can be activated at low temperatures is preferably selected for assembly with the rest of the structure 300. As a result, it is possible to form a structure comprising a plurality of substrates that are electrically connected together.

  If structure 300 comprises one or more adjustment sublayers, structure 300 is formed from a getter material whose activation temperature is further reduced from the base (first substrate 40), thereby making the upper component excessive It can protect against temperature or, conversely, increase diffusion in getters with low activation temperatures and further enhance the strength of intermetallic bonds.

  Next, an example of a method for forming the structure 300 will be described.

  First, a layer of getter material 110a, 110b is deposited on the substrates 40 and 50. Next, layers of getter material 110a, 110b are formed by photolithography and etching of each of these layers. The substrates 40 and 50 are then connected together, for example, by thermocompression of layers of getter material 110a, 110b together.

  Next, in order to connect the via hole 80 to the via hole 82, the substrate 50 is polished to a thickness suitable for a technique called “through-silicon via hole” or TSV. These steps are then repeated to connect the substrate 60 to the substrate 50 and the via holes 80 to the via holes 84 using the getter material layers 112a, 112b. Thus, it is possible to laminate a plurality of substrates, make electrical connections between all the substrates, and / or pull out electrical contacts on either side of the final assembly.

  In one variation of structure 300, it is possible that the assembly between components is not done by two layers of getter material, but by a layer of getter material and an oxide and / or nitride layer. is there. For this purpose, a layer of getter material 110a is deposited on the substrate 40, and then this layer of getter material is formed by photolithography and etching steps. The back surface of the substrate 50 is then oxidized, and then a layer 110 of getter material is deposited on the oxidized back surface of the substrate 50. Next, in order to connect the via hole 80 to the via hole 82, the substrate 50 is polished and thinned to conform to the TSV technology. The oxide layer also serves as a stop layer during the etching of silicon, and forms the through via hole 82. Next, the base material 60 is assembled on the base material 50 in the same manner as the base material 50 is assembled on the base material 40, and the via hole 80 is substantially connected to the via hole 84.

  Compared to prior art structures, the connection process can be performed on a wafer scale without the use of brazing or any other process that requires a liquid phase when making structure 300. It is possible to connect multiple substrates without worrying about melting of brazing. In this case, the structure 300 becomes stronger as the heat balance increases.

  Also, the choice of getter material adjusts the connection temperature of the substrate on the already made structure 300, but also adjusts the conductivity of the getter material. Finally, a connection is made, followed by a thinning and / or polishing step of the final substrate, for example making a microdevice.

  Thus, for example, to form a three-dimensional stack of similar structures, such as a substrate, and / or a microelectronic component, for the purpose of forming a device having multiple functions on a surface equivalent to that of a single component Is possible.

10 Encapsulation structure
12 Base material
14 devices
16 cavity
18 Cover
20 Sealing beads
22 Getter material
24 Getter material pieces
30 Encapsulation structure
40, 50, and 60 substrates
80 Beer Hall
82 Beer Hall
84 Beer Hall
100 structure
101 hollow
102 First substrate
104 devices
106 cavity
108 Second base material
110 First part of getter material
110a, 110b, and 112a, 112b layers of getter material
111a, 111b Part of getter material 110a, 110b
112 Second part of getter material
114 First part
116 Second part
118 Second substrate
200 structure
202 Electrical contacts
204 Electrical contacts
206 faces
300 structure
302 and 304 cavities

Claims (24)

At least one first substrate (40, 102) attached to said first substrate (40, 102) using at least one first substrate (40, 102) and at least one adhesive interface (110a, 110b, 112, 114). Structure (100, 200, 300) comprising at least one cavity (106, 302) defined by two substrates (50, 108), wherein at least one first portion of at least one getter material The first part (114) of (110, 110a) forms part of the adhesive interface (110a, 110b, 112, 114) and the first part (110, 110a) of the getter material. 2 part (116) is disposed in the cavity (106, 302), and the first part (110, 110a) of getter material is the first substrate (40, 302). 02) or in contact with the second substrate (50, 108), and the adhesive interface (110a, 110b, 112, 114) is the said part of the first part (110, 110a) of getter material And further including at least a portion of at least one second portion (110b, 112) of at least one getter material thermocompression bonded to the first portion (114), the second portion (110b, 112) of getter material comprising: To contact the second substrate (50, 108) when the first portion (110, 110a) of getter material is arranged to contact the first substrate (40, 102). Or when the first portion (110, 110a) of getter material is placed in contact with the second substrate (50, 108), the first substrate (40 , 102) It is located in so that,
A structure (100, 200, 300) in which the getter materials undergo interdiffusion without melting .   The structure (100, 200) of claim 1, wherein the second substrate (108) forms a cover.   The structure (100, 200) of claim 1 or 2, wherein the cavity (106) is hermetically sealed.   The structure (100, 200) according to any one of claims 1 to 3, wherein the first part (110) and / or the second part (112) of getter material is a thin layer.   The adhesive interface is a portion of the first substrate (102) made of oxide and / or nitride and / or glass, and / or the second made of oxide and / or nitride and / or glass. The structure (100, 200) according to any one of claims 1 to 4, further comprising a portion of a substrate (108).   The structure (100, 200) according to any one of claims 1 to 5, wherein the getter materials of the first part (110) and the second part (112) of getter material have different thermal activation temperatures. ). The structure (100, 200) of claim 6, wherein the thermal activation temperature of the first portion ( 110 ) of getter material is lower than the thermal activation temperature of the second portion (112) of getter material. ).   At least one first electrical contact (80, 202) disposed in contact with and / or within the first substrate (40, 102). , And at least one second electrical contact (82, 82) disposed in contact with and / or within the second substrate (50, 108). 204), wherein the first electrical contact (202) and the second electrical contact (204) are the first portion of getter material (110a, 110b, 112, 114) that forms the adhesive interface (110a, 110b, 112, 114). The structure (200, 300) according to any one of the preceding claims, wherein the structures (110, 110a) and a part of the second part (112, 110b) are electrically connected together using at least a part thereof.   The structure (100, 200) of any one of claims 1 to 8, further comprising a device (104) disposed within the cavity (106).   The structure (100) of any preceding claim, further comprising at least one other portion (118) of at least one getter material disposed within the cavity (106). Said first portion of getter material (110 and 110a) is at least one of the first of the at least one material suitable for modifying the thermal activation temperature of the first portion of the getter material (110 and 110a) One portion is used to contact the first substrate (40, 102) or the second substrate (50, 108) and / or the second portion (110b) of getter material 112) using the at least one second portion of at least one material suitable for modifying the thermal activation temperature of the second portion of the getter material (110b, 112). The structure (100, 200, 300) according to any one of the preceding claims, arranged to be in contact with a substrate (50, 108) or the first substrate (40, 102), respectively.   The portion of the second portion (110b, 112) of getter material is molecularly bonded to the first portion (114) of the first portion (110, 110a) of getter material. The structure (100, 200, 300) according to any one of 1 to 11. A method for forming a structure (100, 200, 300) comprising at least:
Forming at least one first portion (110, 110a) of at least one getter material in contact with the first substrate (40, 102) or the second substrate (50, 108); ,
At least one second part (110b, 112) of at least one getter material such that the first part (110, 110a) of getter material is in contact with the first substrate (40, 102); In contact with the second substrate (50, 108) or when the first portion (110, 110a) of getter material is in contact with the second substrate (50, 108). Forming so as to contact the first substrate (40, 102) when arranged to do so;
The second part by thermocompression bonding a first part (114) of the first part (110, 110a) of getter material to at least a part of the second part (110b, 112) of getter material; The substrate (50, 108) is attached to the first substrate (40, 102) and is defined by the first substrate (40, 102) and the second substrate (50, 108). Forming at least one cavity (106, 302), wherein a second portion (116) of the first portion (110, 110a) of getter material is disposed within the cavity (106), viewing including the door,
A method for forming a structure (100, 200, 300) wherein the getter materials undergo interdiffusion without melting .   Before the step of forming the first portion (110) of getter material, the second substrate (108) is applied to the first substrate (102) and then in the cavity (106). Forming at least one device (104) in the first substrate (102) and / or in contact with the first substrate (102) to be disposed in 14. The method of claim 13, further comprising:   The step of forming the first portion (110) of getter material includes the first substrate (102) or the second substrate (as a thin layer of the first portion (110) of getter material). The method according to claim 13 or 14, comprising at least one step of depositing in contact with 108).   The step of adhering the second substrate (50, 108) to the first substrate (40, 102) includes the first portion (110, 110a) of the first portion (110, 110a) of getter material. The method according to any one of claims 13 to 15, comprising using adhesion by molecular adhesion 114) to said part of said second part (110b, 112) of getter material.   The method according to claim 16, further comprising a connecting step by heat treatment of the molecular adhesion after performing the molecular adhesion.   The step of forming the first portion (110) or the second portion (112) of getter material in contact with the second substrate (108) also includes the second substrate (108). At least one other portion (118) of getter material to the second substrate (108) such that it is disposed within the cavity (106) after the substrate is attached to the first substrate (102). The method according to claim 13, wherein the method is formed so as to come into contact. Prior to the step of attaching the second substrate (108) to the first substrate (102) and forming the first portion (110) and the second portion (112) of getter material After the step of protecting the first portion (110) and / or the second portion (112) of the getter material, comprising oxides and / or nitrides, the protection removed during the step of depositing Oxidation and / or nitridation of the first part (110) and / or the second part (112) of getter material carried out in a dry atmosphere of diatomic oxygen and / or diatomic nitrogen to form a layer The method according to any one of claims 13 to 18, further comprising a step. Said oxidation and / or nitridation step is carried out under a pressure in the range from 1000 mbar to 10 ⁻² mbar and / or under a temperature in the range from 50 ° C. to 120 ° C. and / or from 1 minute to 10 20. The method of claim 19, wherein the method is performed over a period of time up to minutes. Between the step of the oxidation and / or the adhesion with the nitride step, activity of said first portion (110) and / or the second portion of the getter material activity temperature is the lowest (112) Performing a step of heat treatment of the first part (110) and / or the second part (112) of getter material at a temperature 50 to 150 ° C. lower than the crystallization temperature and under a secondary vacuum 21. The method of claim 19 or 20, further comprising a step. The first portion (110, 110a) and the second portion (110b, 112) of getter material are at least a first electrical contact (80, 202) and a second electrical contact (82, 204), respectively. And one of the first electrical contact and the second electrical contact (80, 202) is in contact with the first substrate (40, 102) and / or Or disposed within the first substrate (40, 102), and the other of the first electrical contact and the second electrical contact (82, 204) is the second substrate (50, 102). 108) in contact with, and / or the the second substrate (50,108) within, disposed, the first portion of the gate jitter material (110 and 110a) and said second portion ( 110b, 112) using the first The method according to any one of claims 13 21, vapor contacts (80,202) and said second electrical contact (82,204) is electrically connected together. Prior to the step of forming the first portion (110) of getter material, at least one of at least one material suitable for modifying the thermal activation temperature of the first portion (110) of getter material One first portion is formed in contact with the first substrate (102) or the second substrate (108), and the first portion (110) of getter material is at least of the material. The method further includes forming on the first portion and / or the method includes forming the second portion (112) of getter material prior to forming the second portion (112) of getter material. ) Contacting at least one second portion of at least one material suitable for modifying the thermal activation temperature of said second substrate (108) or said first substrate (102), respectively I will do it Formed, the method according to any one of claims 13 22 wherein the second portion (112) further comprises a step formed in said second portion of at least the material of the getter material.   After attaching the second substrate (108) to the first substrate (102), the one or more getter materials (116, 118) disposed within the cavity (106). 24. A method according to any one of claims 13 to 23, further comprising one or more thermal activation steps.

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